A persistent danger in the use of hot water heaters is possible asphyxiation by gas resulting from improper combustion as a result of down drafts. The design of various types of hot water heaters must therefore meet severe code requirements, particularly with respect to the inlet air opening.
A particularly dangerous situation exists in mobile homes such as trailer homes or campers wherein their location may be in an area of very high winds. It is not uncommon for such winds to reach 40 to 50 miles per hour and without proper design, suction conditions can develop when such winds blow past the air inlet. High velocity winds passing directly into the air inlet on the other hand could extinguish the pilot light or possibly the entire burner flame.